126 
ME.  J.  H.  COOKE  OK  THE  MAPvLS  AXD 
[Feb.  1893, 
The  organic  remains  which  occur  in  both  the  yellow  and  the  bine 
clays  are,  as  a  rule,  completely  mineralized,  their  substance  being 
replaced  by  peroxide  of  iron.  It  was  on  this  account  that  so  large 
a  proportion  of  the  fossils  which  I  submitted  to  Prof.  Capellini  for 
identification  were  pronounced  to  be  unrecognizable. 
The  most  characteristic  fossils  of  the  formation  are  the  ‘  sepios- 
taires  ’  of  a  Sepia,  the  casts  of  several  species  of  Nautilidae,  and  the 
shells  of  Pecten  Koheni,  all  of  which  are  very  numerous. 
Several  species  of  echinoderms  occur,  none  of  which  are  peculiar 
to  the  Clays,  for  they  are  also  found  in  the  nodule-beds  of  the 
underlying  Globigerina-WmQStone. 
The  mollusca,  the  majority  of  which  are  in  the  form  of  casts, 
are  represented  by  47  species.  The  very  incomplete  state  of  our 
present  knowledge  of  the  Globigerina- limestone  fossils  will  not 
admit  of  trustworthy  comparisons  being  drawn  between  them  and 
the  Clay  mollusca.  I  am,  however,  now  at  work  on  that  formation, 
and  it  may  be  worth  while  to  note  here  that  the  general  facies  of  the 
fossils  of  the  Clays  has  very  much  more  in  common  with  the  Globi- 
gerina- limestone  fossils  than  with  those  of  the  Greensands.  The 
Pectinidse  of  the  Clays  and  the  Greensands  were  critically  examined 
by  Dr.  Simonelli,  of  Pologna,  and  of  the  six  species  found  in  the 
former  bed  all,  with  the  exception  of  P.  Koheni ,  occur  in  the 
Globigerina-limestone,  whereas  P.  dubius  and  P.  Reussi  were  the 
only  species  found  to  be  common  to  the  Clays  and  Greensands. 
P.  denudatus  is  very  abundant  both  in  the  Globigerina- limestone 
and  in  the  Clays. 
The  more  calcareous  parts  of  the  Clays  are  made  up  almost 
entirely  of  foraminifera.  Dr.  John  Murray  enumerates  122  species 
in  his  paper,  but  to  this  number  I  have  been  able  to  add,  with  the 
assistance  of  Mr.  E.  A.  Earland,  31  more,  the  names  of  which  are 
appended  (p.  128).  The  blue  varieties  of  the  Clays  appear  to  be 
the  richest  in  foraminifera,  and  they  are  generally  in  a  good  state 
of  preservation.  Where,  however,  the  Clays  are  overlain  by  the 
Greensands,  large  patches  composed  almost  entirely  of  foraminifera 
extend  to  depths  varying  from  6  to  18  inches  into  the  Clay,  thus 
presenting  the  appearance  of  pockets.  The  most  numerous  species 
found  in  these  ‘  pockets  ’  are  small  Globigerince  associated  with  Trun- 
catulina  lobatula.  Of  the  foraminifera  found  in  the  Globigerina- 
limestone  94  per  cent,  also  occur  in  the  Clays ;  but  of  those  found 
in  the  Greensands  only  37  per  cent,  are  common  to  the  Clays. 
Eish-remains  are  not  very  abundant,  and  those  that  do  occur  are 
so  badly  preserved  as  to  be  scarcely  recognizable.  Teeth  and 
vertebras  of  sharks  are  fairly  common  ;  teeth  of  Chrysophrys  are  rare ; 
and  teeth  and  spines  of  JEtobatis ,  Myliobatis ,  and  Diodon  are  occa¬ 
sionally  met  with.  Large-sized  fragments  of  bones  of  whales, 
dugongs,  and  other  mammals  are  very  abundant,  but  are  badly 
preserved. 
